CIRCUIT ARRANGEMENT FOR THE CONTROL OF A SERIES MOTOR BY A TWO-QUADRANT CONVERTER WITH A CONTINUOUS CONTROL OF FIELD CURRENT

The invention concerns the circuit arrangement of power circuit of a traction drive with series motor allowing, in the running and braking regimes, independent control of the current of the motor armature and excitation current and by the single switchover of one terminal of the armature to the second terminal of current supply allowing the change in direction of revolution of the motor. The circuit arrangement is based on the use of a two-quadrant converter formed by switch-on/switch-off elements (1,2) for control of the running, recuperation and excitation current in all regimes. The power circuit consists of a series combination of the first switch-on/switch-off element (1) with anti-parallel connected diode (11), the first closing diode (3), second closing diode (4) and second switch-on/switch-off element (2) with anti-parallel connected diode (21). Connected in parallel to the series combination of the first closing diode (3 and second closing diode (4) is a excitation coil (5) of the series motor and connected to the centre between the series connected first closing diode (3) and second closing diode (4) is one terminal of the armature (6) of the direct-current series motor, whilst the second terminal of the armature (6) is connected with one terminal of the source of direct current.